Chillon Castle on Lake Geneva, where Jewish prisoners were questioned on false charges of well poisoning in 1348.

Photo: “Château de Chillon” by Shesmax, via Wikimedia Commons, CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0), cropped and color-adjusted.

 

Well Poisoning and the Black Death

 

When plague struck Europe in 1348, Jews were falsely accused of poisoning the wells, and the lie outlived the disease.

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First published: September 28, 2026

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The Claim

In 1348 and 1349, as the Black Death swept across Europe, a rumor spread from town to town. The plague, it said, was not a natural disaster but a crime. Jews had secretly put poison into wells, springs and fountains to destroy Christendom.

 

The story came with details. A rabbi in Toledo or Chambéry had supposedly made the poison and sent it out in small leather pouches. Jewish messengers then dropped it into water supplies from Lake Geneva to Venice and southern Italy.

 

None of it was true. But the accusation was written down, copied and sent from city to city as if it were evidence. Thousands of Jews were killed because of it.

 

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What Actually Happened

The Black Death reached Europe in 1347 and spread along trade routes over the next several years. It killed perhaps a third of Europe's population. No one at the time knew what the disease was or how to stop it.

 

Violence against Jews began early. On the night of 12–13 April 1348, Palm Sunday, a mob attacked the Jewish street in Toulon, in Provence, and killed about 40 people. Historians cannot firmly link that attack to a poisoning charge. The organized version of the accusation, backed by official records, came later that year, farther north.

 

 

The Confessions at Chillon

In the autumn of 1348, officials of Amadeus VI, Count of Savoy, arrested Jews living around Lake Geneva. At the Castle of Chillon, near Villeneuve and Montreux, five prisoners were questioned between 15 September and 18 October 1348.

 

The first was Balavigny, a Jewish surgeon from Thonon. On 15 September he was "put to the question," the medieval phrase for torture. Afterward he "confessed" that a Rabbi Jacob, said to have come from Toledo, had sent him poison in a leather pouch with orders to put it in the town's wells. The other prisoners were tortured in turn and named more "accomplices."

 

A second group of five was questioned at the castle of Châtel on 10 and 11 October 1348. One of them, Agimet of Geneva, "confessed" on 10 October to poisoning a cistern in Venice and wells in southern Italy. According to the record, he also named a public fountain at "Toulouse." Asked whether anyone had died, he said he did not know.

 

The records show how the system worked. A prisoner was tortured. The next day he "confirmed" his words "without torture," and the confession was written down as if freely given. The castellan of Chillon sent copies to Strasbourg, reporting that "all the Jews living in Villeneuve have been burnt by due legal process." Agimet's confession was later printed in 1698, in an appendix to an edition of the chronicle of the Strasbourg writer Jacob von Königshofen.

 

 

The Pope Said No

Pope Clement VI, at Avignon, rejected the charge. In July 1348 he reissued Sicut Judaeis, the long-standing papal decree that forbade Christians to kill or rob Jews.

 

On 26 September 1348, in the bull known as Quamvis perfidiam, he took on the poisoning rumor directly. The plague, he wrote, "has afflicted and afflicts the Jews themselves and many other races who have never lived alongside them." If Jews were dying too, they could not be the cause. When the order was reissued on 1 October 1348, it added that the accusations were driven by greed for Jewish wealth.

 

The historian Samuel K. Cohn Jr. points to a clear example. England had expelled its Jews in 1290, after the coin clipping trials of 1278–1279. Yet the plague struck England in 1348 all the same.

 

Königshofen wrote that Jews were burned "all the way from the Mediterranean into Germany, but not in Avignon, for the pope protected them there." Across much of the Holy Roman Empire, the pope was ignored.

 

 

Basel and Strasbourg

In Basel, the city council at first doubted the charge. According to Königshofen, citizens marched to the city hall and made the council swear to burn the Jews and admit none for 200 years.

 

On 16 or 17 January 1349, the Jews of Basel were locked inside a wooden house built on an island or sandbank in the Rhine and burned alive. Their children were taken and forcibly baptized. Medieval sources give figures as high as 600 dead. Modern historians doubt that number, and the true toll is uncertain.

 

In Strasbourg, the city's leaders also tried to protect the Jews. At a meeting in Benfeld on 8 February 1349, the Bishop of Strasbourg and the lords of Alsace pressed them to act. Strasbourg's delegates said they "knew no evil" of their Jews. Within days, those leaders were forced out of office.

 

On Saturday, 14 February 1349, St. Valentine's Day, the Jews of Strasbourg were burned on a wooden platform in their own cemetery. Chroniclers put the number at about 2,000. That is not a verified count. Modern historians think it is too high, and lower estimates exist. What is certain is that the community was destroyed. Those who accepted baptism were spared.

 

Debts owed to Jews were cancelled and their money divided up. Königshofen wrote bluntly: "The money was indeed the thing that killed the Jews."

 

But money was not the whole story. Cohn and the historian Tzafrir Barzilay show that the killings were usually organized by officials, not only by mobs. City councils, nobles, bishops and castle officials gathered the "evidence," held the trials and ordered the burnings. Cohn argues that these leaders came to believe Jews truly meant to destroy Christendom, and then acted "with cold calculation" through legal process.

 

Often the killing came before the plague did. Basel's Jews were murdered in January 1349, and the plague reached the city that May. Killing Jews protected no one.

 

 

How It Became a Jewish Stereotype

The 1348 charge followed a model set a generation earlier.

 

The Lepers' Plot, 1321: In southwestern France, local officials accused lepers of poisoning wells, and the story grew more elaborate as it spread. Months later, nobles in central France claimed that Jews were behind the plot. The same script of secret poison, a hidden network and forced confessions was ready to use again in 1348.

 

First targets, 1348: When plague arrived, the earliest poisoning accusations fell on beggars, vagrants and travelers. Jews became the main suspects as the charge moved north into Savoy and Alsace.

 

What set 1348 and 1349 apart was the scale, and the paperwork. Cities wrote to one another asking for proof, and "confessions" were copied and passed along. Of the replies to Strasbourg that survive, only the one from Cologne questioned the charge.

 

The result was a lasting image: the Jew as a secret poisoner, part of a hidden network, taking orders from distant leaders and able to harm a whole society at once. Jews were killed in at least two hundred towns and villages, and the major Jewish communities of the Rhineland were nearly wiped out.

 

The charge also fed older lies. Like the blood libel, it cast Jews as secret murderers of Christians. Like the coin clipping accusation, it was tied to money.

 

 

Modern Mutations

The medieval details faded. The core idea, that Jews secretly spread poison or disease to harm everyone else, did not.

 

Disease propaganda: In March 1941, a Nazi poster in Polish, put up in German-occupied Poland, portrayed Jews as disease-carrying lice ("Jews are lice; they cause typhus"), even though the typhus epidemics came from the hunger and overcrowding that German policy forced on the ghettos.

 

The "Doctors' Plot": On 13 January 1953, Soviet newspapers announced the arrest of nine doctors, at least six of them Jewish. They were accused of poisoning Soviet leaders and of serving "international Jewry." In April 1953 the charges were declared false, and officials admitted the confessions had been obtained by torture, just as at Chillon six centuries earlier.

 

Pandemic conspiracy theories: When COVID-19 spread in 2020, researchers tracked online claims that Jews had created the virus, were spreading it on purpose, or planned to profit from it. Monitoring groups compared these claims directly to the well poisoning charge of 1348.

 

The details change with each crisis. The pattern stays the same. A disaster strikes, fear looks for someone to blame, and Jews are cast as the hidden cause.

 

 

Why It Matters

The well poisoning accusation shows how a lie can dress itself up as evidence. The confessions of 1348 carried official seals, notaries' signatures and specific names and places. They were still false, because they came from torture.

 

It also shows that clear thinking was available at the time. Pope Clement VI made a simple, logical argument: Jews were dying of the plague too, and it struck peoples who had never lived alongside Jews. Many people chose not to listen.

 

When a disaster strikes, notice who gets blamed and why. A story that blames a hidden group for suffering everyone shares is one of the oldest patterns of antisemitism. Recognizing it is the first step to refusing it.

 

Sources

• Barzilay, Tzafrir. Poisoned Wells: Accusations, Persecution, and Minorities in Medieval Europe, 1321–1422. The Middle Ages Series. Philadelphia: University of Pennsylvania Press, 2022.

• Dorin, Rowan. Review of Poisoned Wells, by Tzafrir Barzilay. The Medieval Review 23.03.13 (2023). https://scholarworks.iu.edu/journals/index.php/tmr/article/view/36066

• Cohn, Samuel K., Jr. "The Black Death and the Burning of Jews." Past & Present, no. 196 (August 2007): 3–36. doi:10.1093/pastj/gtm005.

• Horrox, Rosemary, trans. and ed. The Black Death. Manchester Medieval Sources Series. Manchester: Manchester University Press, 1994. See the chronicle of Heinrich of Diessenhofen, the examinations at Chillon and Châtel, and the mandate of Clement VI (pp. 208–222).

• Marcus, Jacob Rader. The Jew in the Medieval World: A Source Book, 315–1791. First published 1938; revised edition with an introduction by Marc Saperstein, Cincinnati: Hebrew Union College Press. Section "The Black Death and the Jews, 1348–1349." Online transcription: Internet Jewish History Sourcebook, Fordham University, https://sourcebooks.fordham.edu/jewish/1348-jewsblackdeath.asp

• Nirenberg, David. Communities of Violence: Persecution of Minorities in the Middle Ages. Princeton: Princeton University Press, 1996 (updated edition 2015). See chapter 2, "France, Source of the Troubles: Shepherds' Crusade and Lepers' Plot (1320, 1321)," and the epilogue, "The Black Death and Beyond."

• Winkler, Albert. "The Approach of the Black Death in Switzerland and the Persecution of Jews, 1348–1349." Swiss American Historical Society Review 43, no. 3 (2007): 4–23. https://scholarsarchive.byu.edu/facpub/1813

• Blumenkranz, Bernhard. "Toulon." Encyclopaedia Judaica, via Jewish Virtual Library. https://www.jewishvirtuallibrary.org/jsource/judaica/ejud_0002_0020_0_19973.html

• Ginsburger, Moïse. "La première communauté israélite de Strasbourg (suite et fin)." Web edition, A.S.I.J.A. (Judaïsme d'Alsace et de Lorraine). http://www.judaisme-alsalor.fr/histoire/villes/strasbrg/premiere/prem-2.htm

• Encyclopaedia Britannica. "Doctors' Plot." https://www.britannica.com/event/Doctors-Plot

• United States Holocaust Memorial Museum, Experiencing History. "Propaganda Poster: 'Jews Are Lice: They Cause Typhus.'" https://perspectives.ushmm.org/item/propaganda-poster-jews-are-lice-they-cause-typhus

• United States Holocaust Memorial Museum, Holocaust Encyclopedia. "Antisemitic poster published in German-occupied Poland in March 1941." https://encyclopedia.ushmm.org/content/en/photo/antisemitic-poster-published-in-german-occupied-poland-in-march-1941

• Community Security Trust. "Coronavirus and the Plague of Antisemitism." Research briefing, April 2020. https://cst.org.uk/news/blog/2020/04/08/coronavirus-and-the-plague-of-antisemitism

 

 

Last updated: October 3, 2026